The present invention relates to a process for producing a carbonaceous electrode substrate for use in fuel cells comprising two layers of a porous carbonaceous layer and a compact carbonaceous layer or three layers of two porous carbonaceous layers and a compact carbonaceous layer disposed between said two porous carbonaceous layers, wherein said porous carbonaceous layer(s) has elongated holes located nearly in the central region of thickness thereof, characterized by using high polymeric substance as a material for forming said elongated holes.
Hitherto, fuel cells of bipolar-separator type using bipolar-separators obtained by subjecting impermeable graphitic thin plates to rib-working have been known.
On the other hand, electrode substrates of monopolar-type have come to be developed, wherein the one surface of the electrode substrate is provided with ribs and the opposite surface thereof is flat. In a cell formed by such electrode substrates, the gaseous reactant (oxygen or hydrogen) diffuses from the ribbed surface through the substrate to the flat opposite surface.